The European Community Respiratory Health Survey (ECRHS) aimed to investigate variations in asthma prevalence and related factors across Europe. The study involved 33 centers in 11 European countries, seven in five COST states, and 15 in seven other countries. It sought to estimate variations in asthma prevalence, asthma-like symptoms, airway responsiveness, and risk factors, as well as differences in asthma treatment. The protocol outlined sampling strategies, questionnaires, allergy tests, lung function measurements, and blood/urine collection. Data collection sheets and coding instructions were provided in appendices. Asthma is a significant health issue in Europe, with increasing prevalence and mortality rates. The ECRHS aimed to determine whether these trends were due to environmental factors, as previous studies showed rising asthma prevalence in various regions. The study found that asthma prevalence varied widely, with significant increases in urbanized areas, suggesting environmental influences. Factors such as atopy, dietary sodium, and exposure to allergens were considered potential causes. The study also highlighted the role of maternal smoking in increasing asthma risk. The ECRHS was designed to cover all European areas due to significant environmental and cultural variation. It aimed to collect data from at least three areas per country to reduce confounding effects. The study involved two stages: a screening questionnaire and a main questionnaire with further tests. Sample sizes were determined to detect significant variations in asthma prevalence. The study used standardized questionnaires, allergy tests, and lung function tests to assess asthma and related factors. It also measured urinary electrolytes to evaluate sodium levels. Data collection involved training and quality control measures to ensure consistency across centers. The study's findings suggest that asthma is a potentially preventable condition influenced by environmental factors. The ECRHS aimed to provide a comprehensive understanding of asthma prevalence and risk factors across Europe, with results to be analyzed and used for policy development. The study's methodology and findings have implications for public health strategies to address asthma in Europe.The European Community Respiratory Health Survey (ECRHS) aimed to investigate variations in asthma prevalence and related factors across Europe. The study involved 33 centers in 11 European countries, seven in five COST states, and 15 in seven other countries. It sought to estimate variations in asthma prevalence, asthma-like symptoms, airway responsiveness, and risk factors, as well as differences in asthma treatment. The protocol outlined sampling strategies, questionnaires, allergy tests, lung function measurements, and blood/urine collection. Data collection sheets and coding instructions were provided in appendices. Asthma is a significant health issue in Europe, with increasing prevalence and mortality rates. The ECRHS aimed to determine whether these trends were due to environmental factors, as previous studies showed rising asthma prevalence in various regions. The study found that asthma prevalence varied widely, with significant increases in urbanized areas, suggesting environmental influences. Factors such as atopy, dietary sodium, and exposure to allergens were considered potential causes. The study also highlighted the role of maternal smoking in increasing asthma risk. The ECRHS was designed to cover all European areas due to significant environmental and cultural variation. It aimed to collect data from at least three areas per country to reduce confounding effects. The study involved two stages: a screening questionnaire and a main questionnaire with further tests. Sample sizes were determined to detect significant variations in asthma prevalence. The study used standardized questionnaires, allergy tests, and lung function tests to assess asthma and related factors. It also measured urinary electrolytes to evaluate sodium levels. Data collection involved training and quality control measures to ensure consistency across centers. The study's findings suggest that asthma is a potentially preventable condition influenced by environmental factors. The ECRHS aimed to provide a comprehensive understanding of asthma prevalence and risk factors across Europe, with results to be analyzed and used for policy development. The study's methodology and findings have implications for public health strategies to address asthma in Europe.